2.4- Dinitrophenyl Hydrazin

By a similar reaction ethanol gives acetaldehyde (tests, p. 341) and isopropanol gives acetone (tests, p. 345). -Butanol gives butyr dehyde (pleasant characteristic odour and precipitate with 2,4-dinitrophenyl-hydrazine, m.p. 122 ). 

Aromatic ketones usually have relatively high boiling points, but distil with little or no decomposition. Many are solids. The vapours generally burn with a smoky flame. They react with the 2 4-dinitrophenyll hydrazine reagent (Section 111,74,/) or with the phenylhydrazine reagent... 

The acetone test reagent consists of a 0 1 per cent, solution of 2 4-dinitro-phenylhydrazine and is prepared as follows Dissolve 0-25 g. of 2 4-dinitrophenyl-hydrazine in 60 ml. of water and 42 ml. of concentrated hydrochloric acid by warming on a water bath cool the clear yellow solution and dilute to 250 ml. with water. The acetone test is considered negative when 5 ml. of the reagent and 4-5 drops of the distillate give no cloudiness or precipitate of acetone 2 4-dinitro-phenylhydrazone within 30 seconds. After a negative test is obtained, it is stron y recommended that the mixture in the flask be refluxed for 5-10 minutes with complete condensation and then to collect a few drops of distillate for another test. If no acetone is now detected, the reduction is complete. 

Carvone, menthone, acetophenone etc Apply an aadic solution of 2,4-dinitrophenyl-hydrazine, 4-nitrophenylhydrazine or 2,4-dinitro-phenylsemicarbazide onto the previously applied sample solution Aliphatic and aromatic hydra-zones and carbazones can be differentiated by their colors [82]... 

Dinitrophenyl-hydrazine has been successfully employed in the analysis of simple aldehydes, substituted aldehydes, glyoxal and gluteraldehyde (43-45), all the isomers of the C3 to C7 aliphatic ketones (44,45) and in the determination of formaldehyde in tobacco smoke (46). 

GPT activity was determined by the colorimetric method with 2,4-dinitrophenyl-hydrazine (refs. 12,13). Results were calculated on the basis of the calibration prepared from pyruvate, made for each series of determinations. The amount of pyruvate (pmol/cm ) formed during 1 h incubation at 37 °C was assumed as the activity unit. 

Aldehydes 2,4-Dinitrophenyl- hydrazine Formation of colored hydrazones or osazones. It is possible to distinguish between saturated and unsaturated hydrazones using potassium hexacyano-ferrate(III) [5]. [3,4]... 

If an unknown compound gives a positive test with the 2 4-dinitrophenyl-hydrazine reagent, it then becomes necessary to decide whether it is an aldehyde or a ketone. Although the dimedone reagent (Section 111,70,2) reacts only with aldehydes, it is hardly satisfactory for routine use In class reactions. It is much simpler to make use of three other reagents given below, the preparation and properties of which have already been described (Section 111,70). 

Unfortunately, there are no universal methods to detect all types of protein oxidation, because the products formed can be so diverse in nature. However, some forms of protein oxidation can be assayed using chemical modification (Davies et al., 1999 Shacter, 2000). In particular, the formation of carbonyl groups on proteins can be targeted using the reagent 2,4-dinitrophenyl-hydrazine (DNPH). This compound reacts with aldehydes to form 2,4-dinitrophenylhydrazone derivatives, which create chromogenic modifications that can be detected at high sensitivity in microplate assays or Western blot analysis (Buss et al., 1997 Winterbourn et al., 1999). 

Fused thietes often show a different chemical behavior than the thietes themselves. The fused thiete undergoes ring opening much more readily because of greater ring strain, and thus the reaction with 2,4-dinitrophenyl-hydrazine takes a different course (Schemes 15 and 16). 

Unsubstituted 4//-pyran (5) and 4//-thiopyran (7) with 2,4-dinitrophenyl-hydrazine afford identical bishydrazones 503.18,19 Analogous product 504 was obtained from 4//-pyran derivative 68 (X = EtO, Y = Me), whereas a slightly modified precursor possessing Y = Ph provided monohydrazone 505.86... 

Ethylphenylhydrazine and derivs 6 E321—E322 l-ethyi-l-(2,4-dinitrophenyl) hydrazine 6 E322 1 -ethyl-1 -(4-nitrophenyl) hydrazine 6 E322 ethyl-2,4,6-trinitrophenyl hydrazine 6 E322 l-(2,2,2-trinitroethyl)-2-(2,4-[Pg.611]

The carbonyl group is determined by a reaction with 2,4-dinitrophenyl hydrazine which precipitates the 2,4-dinitrophenyl hydrazone of the aldehyde or ketone, which is then filtered off, dried, and weighed. The reaction is... 

Imines of aldehydes are relatively stable while those of ketones are unstable. Derivatives of imines that form stable compounds with aldehydes and ketones include phenylhydrazine, 2,4-dinitrophenyl-hydrazine, hydroxylamine, and semicarbazide. 

The bis-adducts of 3,3-dimethylpentane-2,4-dione with phenyl and 2,4-dinitrophenyl hydrazines 77 [R1 = R2 = Ph, 2,4-(N02)2C6H3] have been obtained (85KGS854 86ZOR1096 88ZOR426), and the irreversible isomerization 77A — 77B (R1 = R2 = Ph) has been observed in benzonitrile solution at 60°C. The analogous isomerization for the 2,4-dinitrophenyl derivative does not take place at all. The isomerization 77A —> 77B (R1 = R2 = Ph) has also been detected in the gas phase under the conditions of the mass-spectrometric experiment. 

Two suitably positioned nitro groups make the halogen-bearing carbon atom in 2,4-dinitro-halobenzenes a favored point of reaction for nucleophilic substitution reactions. Thus, 2,4-dinitrophenyl hydrazine is produced from the reaction of 2,4-dinitrochlorobenzene with hydrazine ... 

The reactivity of the carbonyl group in a,/3-unsaturated dialdoses was studied in more detail. The interaction with phenylhydrazine and its derivatives led to different results. 3-0-Benzyl-l,2-0-cyclo-hexyl idene-5,6-dideoxy-a-D-xyZo-hept-5-e nodialdo-l,4-furanose (56) gave57 a (2,4-dinitrophenyl)hydrazone. Action of (2,4-dinitrophenyl)-hydrazine on derivatives 67 led18 to complex mixtures. In the case of the acetylated derivatives (66), as well as of branched-chain derivatives (69), the interaction with (2,4-dinitrophenyl)hydrazine resulted in the formation of the expected hydrazones (Refs. 24 and 51, respectively). The interaction with phenylhydrazine was, however, proved to proceed by two paths in this case. Only the nitro derivatives (66, R = p-nitrophenyl) and (69, R = p-nitrophenyl) were shown24,51 to form the expected hydrazones. The phenyl derivative 66 (D-galacto, R = Ph) and p-methoxyphenyl derivative 69 (R = p-MeOC8H4) afforded substituted pyrazolines (74) (Ref. 24) and (75) (Ref. 51), respectively, as a result of subsequent intramolecular addition of a... 

Nl. Nakamura, A., and Goto, S., Analysis of protein carbonyls with 2,4-dinitrophenyl hydrazine and its antibodies by immunoblot in two-dimensional gel electrophoresis. J. Biochem. (Tokyo) 119,768-774 (1996). 

This assay is based on the interaction between carbonyl groups, resulting from free radical-modified proteins and 2,4-dinitrophenyl-hydrazine (see Fig. 5.9) (Oliver et al., 1987). As well as isolated proteins, protein in cells can also be studied by this method, as described below. 

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